From amol at stanford.edu Mon Nov 6 12:11:20 2000
From: amol at stanford.edu (Amol Ramesh Joshi)
Date: Mon, 6 Nov 2000 12:11:20 -0800 (PST)
Subject: H2SO4 thermometer
Message-ID:
Hi,
I read a note on wbdiff that the thermometer is broken. The
problem on Coral says TC is broken. Can someone clarify if the sensor was
broken? If the pot was contaminated as a result, has it been cleaned?
Thanks,
- Amol
From beckwith at sunray.snffab.stanford.edu Mon Nov 6 14:32:59 2000
From: beckwith at sunray.snffab.stanford.edu (Sharleen Beckwith)
Date: Mon, 6 Nov 2000 14:32:59 -0800 (PST)
Subject: Sulfuric hot pot
Message-ID:
Due to the questionable state of this hot pot, I am giving it an HCl
clean. This may take several hours. Since I cannot determine the
temperature, I will have to wait a long period of time for the HCl to
cool, then guess when it is safe to aspirate.
I have also emptied both HF tanks. I am leaving them empty, please fill
them as needed.
Sharleen
From beckwith at snf.stanford.edu Mon Nov 6 19:47:56 2000
From: beckwith at snf.stanford.edu (Sharleen Beckwith)
Date: Mon, 6 Nov 2000 19:47:56 -0800
Subject: hot pot problems
Message-ID:
Folks:
Over the weekend the quartz thermocouple sheath in the sulfuric hot pot
broke. When Ray looked at it, the thermocouple appeared to be corroded. In
an effort to keep the diff bench up and running, it was decided that the
thermocouple and quartz sheath from one of the wbnonmetal hot pots could be
put in the wbdiff sulfuric hot pot until the new parts arrive.
Unfortunately, the second thermocouple broke during the switch.
Ray said he will make every effort, first thing in the morning, to replace
the thermocouple in wbdiff. It will take longer to get the quartz sheaths,
so the sulfuric hot pot in wbnonmetal may be down for a few days.
Sharleen
From rcrane at snf.stanford.edu Tue Nov 7 14:54:02 2000
From: rcrane at snf.stanford.edu (Dick Crane)
Date: Tue, 07 Nov 2000 14:54:02 -0800
Subject: wbdiff repair
Message-ID: <3A08880A.FAEB2AA0@snf.stanford.edu>
The wbdiff hot pots will be repaired tomorrow. Thermistors and quartz
sheaths are being shipped UPS red and should arrive here by 1000,
11/8/00. In the future, spare thermistors, locally made covers, and
controllers will be in stock here.
Dick Crane
Technical Director snf
From randythrive at yahoo.com Wed Nov 8 15:03:57 2000
From: randythrive at yahoo.com (Randy True)
Date: Wed, 8 Nov 2000 15:03:57 -0800 (PST)
Subject: wbdiff band-aid fix
Message-ID: <20001108230357.27531.qmail@web3606.mail.yahoo.com>
Wbdiff Users--
The current status of the diff bench is that we are
still waiting for the thermocouple sheath to arrive.
In the meantime, a protocol is being adopted that will
still allows users to diff clean their wafers.
The power to the sulfuric pot must remain off because
of fire concern. It is unplugged in the back. DO NOT
turn it back on. This means that users cannot drain
the sulfuric pot. Ray will drain the pot (but not
refill it) once in the morning and once in the
afternoon. After the pot has been drained, the first
user should fill the pot. Others should continue to
use the bath without adding peroxide for about 2
hours. There will be a sign-up list for filling and
adding peroxide. If you walk up to use the bench more
than 2 hours after it has been filled or since the
last time peroxide has been added, add peroxide.
Please be dilligent about both recording the activity
and not adding peroxide too often. Also, make sure to
go through the wbnonmetal sulfuric before going to the
diff bench.
If you have any concerns or comments, please contact
myself and Ray. Happy cleaning.
__Randy True
__________________________________________________
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From randythrive at yahoo.com Wed Nov 8 15:35:56 2000
From: randythrive at yahoo.com (Randy True)
Date: Wed, 8 Nov 2000 15:35:56 -0800 (PST)
Subject: even better fix
Message-ID: <20001108233556.1100.qmail@web3606.mail.yahoo.com>
So, Ray has done some handy-work and made it possible
for users to drain the sulfuric pot. The power is on
but the heater is diabled (still do not turn it on).
This makes most of the last email moot. I guess
proceed as normal, we just will not know the bath
temp. Look at the log and if someone has changed the
bath or added peroxide recently, it should be OK,
otherwise add peroxide.
__________________________________________________
Do You Yahoo!?
Thousands of Stores. Millions of Products. All in one Place.
http://shopping.yahoo.com/
From beckwith at snf.stanford.edu Wed Nov 8 16:45:42 2000
From: beckwith at snf.stanford.edu (Sharleen Beckwith)
Date: Wed, 8 Nov 2000 16:45:42 -0800
Subject: even better fix
In-Reply-To: <20001108233556.1100.qmail@web3606.mail.yahoo.com>
References: <20001108233556.1100.qmail@web3606.mail.yahoo.com>
Message-ID:
At 3:35 PM -0800 11/8/00, Randy True wrote:
>So, Ray has done some handy-work and made it possible
>for users to drain the sulfuric pot. The power is on
>but the heater is diabled (still do not turn it on).
>This makes most of the last email moot. I guess
>proceed as normal, we just will not know the bath
>temp. Look at the log and if someone has changed the
>bath or added peroxide recently, it should be OK,
>otherwise add peroxide.
My concern is:
if someone empties the Sulfuric:H2O2 when it is too hot
and then hits the quartz hot pot with cold water we may
end up with a cracked quartz hot pot.
We have no replacements for these hot pots and the last time Len
searched for one he could find no one who manufactured them.
I would suggest using the old "empty every 5 days". Just drain out
enough of the liquid to leave room for adding more H2O2 instead of
completely emptying the entire pot...it should be repaired within the
next 5 days.
Someone from SNF should make the final call on this.
At any rate: PLEASE be careful when you are draining and rinsing the hot pot!
Sharleen
From rcrane at snf.stanford.edu Thu Nov 9 12:07:24 2000
From: rcrane at snf.stanford.edu (Dick Crane)
Date: Thu, 09 Nov 2000 12:07:24 -0800
Subject: Hotpot repair
Message-ID: <3A0B03FC.9B8925CC@snf.stanford.edu>
Ok, I am the one who stubbed his toe with the inadvertent bench
shutdown. Given the failure (and lack of spares) of the temperature
sensor for the hot pot and the potential danger of wet bench fires
caused by runaway hot pots, I shut down the hot pot heater with the plan
of using the self heating action of the H2SO4/H2O2 4:1 mix to allow
continued operation of the bench. I was not aware of the drain interlock
preventing use of the pot. Shutting down the bench was not the plan and
I am sorry for the inconvenience caused.
I consider the wbdiff to be a tool of prime importance and is one the
highest maintenance priorities in the fab. Replacement sensors have
arrived and will be installed today, 11/9/00. You may notice that the
quartz sheaths are no longer present. The new sensors, with teflon
covers, have worked well in high, minority carrier lifetime processes.
Metallic contamination through the teflon is not a worry for our
operation. Please see me if you have questions.
The future: On Monday on this week, I started reviewing the high
priority tools to insure an adequate supply of spares. The wbdiff will
soon have a stock of controllers, sensors, general parts and, hopefully,
spare hot pots. The goal is high uptime for this important tool.
Thanks,
Dick Crane
technical Director SNF
From amol at stanford.edu Fri Nov 10 09:41:22 2000
From: amol at stanford.edu (Amol Ramesh Joshi)
Date: Fri, 10 Nov 2000 09:41:22 -0800 (PST)
Subject: Possible contamination of wbdiff and wbnonmetal
Message-ID:
Hi,
Today I found a user doing nonstandard 'cleaning' on wbdiff and
wbnonmtal. He was etching oxide in 20:1 BOE and 6:1 BOE on wbnonmetal and
H2SO4 dip and HCl dip on wbdiff. He was holding just one wafer with teflon
tipped METAL tweezers, no cassette! As most users know, teflon on green
tipped tweezers tends to wear out after some use. So there is a very high
chance that metal may have entered the pots I mentioned above. I do not
need to mention safety issue, no matter how careful one is. I have
shutdown wbdiff and wbnonmetal.
- Amol
From jgarate at snf.stanford.edu Fri Nov 10 11:23:04 2000
From: jgarate at snf.stanford.edu (Jaime Garate)
Date: Fri, 10 Nov 2000 11:23:04 -0800
Subject: Possible contamination of wbdiff and wbnonmetal
References:
Message-ID: <3A0C4B18.57E014B6@snf.stanford.edu>
Hi,
I have talked to the user responsible for this. Not only for the safety
issue, but for the cross-
contamination issue. He is involve on the clean up. The WBNONMETAL- has
been decontaminate and it is
okay to use. The WBDIFF- still down under decontamination.
(1) You are not allow to dip your metal tweezers at these wet benches at
all!!!
(2) You are not allow to go from 20:1 or 6:1 on wbnonmetal to a H2S04
dip and
HCL dip on wbdiff at all!!!
(3) We are all members so please follow the procedures and work safely.
Thanks, Jaime Garate
Amol Ramesh Joshi wrote:
>
> Hi,
>
> Today I found a user doing nonstandard 'cleaning' on wbdiff and
> wbnonmtal. He was etching oxide in 20:1 BOE and 6:1 BOE on wbnonmetal and
> H2SO4 dip and HCl dip on wbdiff. He was holding just one wafer with teflon
> tipped METAL tweezers, no cassette! As most users know, teflon on green
> tipped tweezers tends to wear out after some use. So there is a very high
> chance that metal may have entered the pots I mentioned above. I do not
> need to mention safety issue, no matter how careful one is. I have
> shutdown wbdiff and wbnonmetal.
>
> - Amol
From eap at gloworm.Stanford.EDU Sat Nov 11 17:10:49 2000
From: eap at gloworm.Stanford.EDU (Eric Perozziello)
Date: Sat, 11 Nov 2000 17:10:49 -0800 (PST)
Subject: 6:1 pot on wbdiff decontaminated using HCl/H2O2.
Message-ID: <200011120110.RAA00776@gloworm.Stanford.EDU>
Hi All,
I found a note on the bench this AM that the 6:1 pot had not
yet been decontaminated. It was empty. So while I changed
the other chemicals, I heavily rinsed it, filled with HCl/H2O2,
let it sit, drained, and rinsed and filled w/ DI, drained, ec,
and finally refilled with 6:1.
I left a note to this effect on the bench. I hope this
procedure is correct, as we've used this before in these cases.
I didn't use this pot after changing, so if there's
From beckwith at snf.stanford.edu Tue Nov 14 15:51:08 2000
From: beckwith at snf.stanford.edu (Sharleen Beckwith)
Date: Tue, 14 Nov 2000 15:51:08 -0800 (PST)
Subject: no spray rinse in the left dump rinser...
Message-ID:
this means the handles are not being rinsed at all (using the right dump
rinser is not an option, so I suggest you take the cassette handle off and
put it in the bottom of the dump rinser. Run the standard 6 cycles. Put the
handle back on the cassette.
Sharleen
From beckwith at snf.stanford.edu Tue Nov 14 15:58:25 2000
From: beckwith at snf.stanford.edu (Sharleen Beckwith)
Date: Tue, 14 Nov 2000 15:58:25 -0800 (PST)
Subject: Who left the HCl hot pot empty?????
Message-ID:
When I came in around noon today the HCl hot pot was empty. PLEASE do NOT
leave hot pots empty without leaving a note and sending e-mail to the user
list (see the e-m address above) explaining why you are doing something
like this. I had no way of knowing if there was a
problem with the hot pot or not. Given the history of the past two weeks,
I assumed the worst (someone had contaminated it) and cleaned it with HCl
before I used it. This caused a tremendous back log of people who needed
to use the bench (not to mention "wasting" a substantial amount of MY
time).
We all have to share the equipment in this lab. You are not operating in a
vacuum. Whatever you do affects all the people who come after you. Please
remember this when you are in the lab!
Sharleen
From grupp at snow.stanford.edu Sun Nov 19 00:54:13 2000
From: grupp at snow.stanford.edu (Dan Grupp)
Date: Sun, 19 Nov 2000 00:54:13 -0800 (PST)
Subject: Bench reserved Sunday morning for chemical change
Message-ID:
No one is signed up for Sun morning, so i don't expect this to be of any
inconvenience. Please leave the heaters OFF sunday morning so chemicals
may be changed.
Thanks,
Dan
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Dr. Daniel Grupp, Visiting Scholar
Center for Integrated Systems
Stanford University
Stanford, CA 94305
(650) 724-6911
FAX: 723-4659
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